The present invention relates to computer systems used to define a target program in response to a user's touching a screen of the system, and more particularly relates to means to make full use of the intelligence of a touchscreen system.
A touchscreen is disclosed in a co-pending application Ser. No. 533,384 by Thomas Earl Kilbourn and Scott Robert McClelland. As mentioned in that application, the touchscreen provides an effective source of information about the movement of an operator's touch action on a display surface such as a CRT. Other devices have been developed that allow the user to select a position on the display and once selected, to initiate whatever operation is associated with that position. These devices include such apparatus as "mice", graphics stylus/pads and light-pens. These devices actually consist of two mechanisms, one to provide position information and one to provide activation information to the target program. In these systems, it is up to the target program to translate the position information into the corresponding operation directive and to cause that operation to be performed when activation is required by the user. The target program is thus involved in the selection/activation process even if the operation to be performed is external to the target program. These systems usually require the use of a cursor for position feedback to the user so that the user can see what position is currently being selected. Thus, there is no intelligence inherent in these systems. They simply provide position and activation information to the target program.
In other systems, mechanical function keys are provided on the physical keyboard arranged in a manner such that they correspond in relative position to labels that are displayed along the bottom of the display screen. By performing a visual correlation between the position of a label on the display and the position of a function key on the keyboard, the user is able to select the appropriate function key to be pressed in order to perform the operation desired. Because the function labels are separate from the function key, it is possible to make an erroneous selection.